* {
  margin: 0;
  padding: 0;
  list-style: none;
  box-sizing: border-box;
}
.mask{
    width:100%;
    height:100%;
    position: fixed;
    top:0;
    left:0;
    background: rgba(0,0,0,.3);
}


.content{
    /* 上下左右居中 */
    position: fixed;
    top:50%;
    left:50%;
    transform: translate(-50%,-50%);
    background: #fff;
    width:300px;
    height:150px;
    text-align: center;
    border-radius: 25px;;
}

.content button{
    width:80px;
    height:36px;
    margin:10px 10px;
}

.content h2{
    margin-top: 10px;
}